This invention relates to external, gas powered programmable infusion devices, and in particular embodiments, to an external gas powered programmable infusion device that utilizes a disposable medication cartridge with gas power source.
Insulin must be provided to people with Type I, and many with Type II diabetes. Traditionally, since it cannot be taken orally, insulin has been injected with a syringe. More recently, use of external infusion pump therapy has been increasing, especially for delivering insulin for diabetics using devices worn on a belt, in a pocket, or the like, with the insulin delivered via a catheter with a percutaneous needle or cannula placed in the subcutaneous tissue. For example, as of 1995, less than 5% of Type I diabetics in the United States were using pump therapy. Currently, of the over 900,000 Type I diabetics in the U.S., about 7% use insulin pump therapy, and the percentage is now growing at an absolute rate of over 2% each year. Moreover, the number of Type I diabetics is growing at 3% or more per year. In addition, growing numbers of insulin using Type II diabetics are also using external insulin infusion pumps. Physicians have recognized that continuous infusion provides greater control of a diabetic""s condition, and are also increasingly prescribing it for patients. In addition, medication pump therapy is becoming more important for the treatment and control of other medical conditions, such as pulmonary hypertension, HIV and cancer. Although offering control, pump therapy can suffer from several complications that make use of traditional external infusion pumps less desirable for the user.
For instance, one drawback is that traditional external pumps for profiled delivery of insulin and other drugs that require accurate titration are generally complex and expensive. Regarding costs, traditional external insulin pumps for treating Type 1 diabetes typically cost about $5,000 and the disposables cost about $800 to $1,200 per year. Generally, Type 2 diabetics often spend $3-$8 per day just for an oral medication rather than insulin. Thus, managed care providers are generally resistant to spending $5,000 for a pump, especially for a Type 2 diabetic, but seem less concerned about reimbursing for disposables or for the costly drugs.
Traditional external pumps are very sophisticated, with many safety features and checks. However, for some applications, such as for a Type 2 diabetic, a simpler and less expensive non-programmable pump system would often suffice. Conversely, programmability may still be desired or necessary to provide tighter control and flexibility. In addition, a programmable pump provides greater flexibility to use the external pump over a wider range of treatments and for a greater variety of medications.
It is an object of an embodiment of the present invention to provide an integrated diabetes management system, which obviates for practical purposes, the above-mentioned limitations.
According to an embodiment of the invention, an external infusion device system for infusing a fluid into a patient, the system includes a reusable infusion device housing, a gas power source and disposable reservoir. The gas power source is for generating a gas to expel the fluid from the fluid reservoir. The disposable reservoir is insertable into the reusable infusion device housing to infuse the fluid into the patient. The disposable reservoir includes a reservoir housing, a fluid reservoir, an outlet, an expansion chamber and a regulating valve assembly. The fluid reservoir is within the reservoir housing for containing the fluid to be infused into the patient. The outlet is in the reservoir housing and provides a path through which the fluid is expelled to be infused into the patient. The expansion chamber is disposed between the gas power source and the fluid reservoir to receive the gas from the gas power source. The expansion member expands into the fluid reservoir to expel the fluid from the fluid reservoir. The regulating valve assembly is disposed between the fluid reservoir and the outlet to set a predetermined threshold pressure that must be exceeded to permit fluid to be expelled from the fluid reservoir through the outlet. In preferred embodiments, the fluid to be infused is a medication. Also, the regulating valve assembly sets the predetermined threshold pressure at a pressure somewhat above standard atmospheric pressure, such as greater than 1.05 atmospheres.
In particular embodiments, the gas power source utilizes electrolysis to generate the gas. In other embodiments, the gas power source includes a housing, and the gas power source uses the housing of the gas power source as an electrode. Also, the disposable reservoir can include a pressure sensor coupled to the gas power source to determine a pressure in the expansion chamber to detect an occlusion. In preferred embodiments, the disposable reservoir has a circular cross-section, while in other embodiments, the disposable reservoir has an oval cross-section. Preferably, the expansion chamber is formed as a sack, and in some embodiments the sack has a circular cross-section. In still further embodiments, the regulating valve assembly is compressed prior to use to set the predetermined threshold pressure. In particular embodiments, the gas power source is contained in the disposable reservoir. In other embodiments, the gas power source is contained in the device housing and engages with the disposable reservoir.
Other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, various features of embodiments of the invention.